When estimating beams, girders, and columns, it is important to estimate not only the number of structural steel members needed but also the weight of each member so the crane can be properly sized. General contractors of ten estimate beams, girders, and columns based on the weight of the steel member and adds a percentage to the weight to allow for connections and bolts because the design of the connections and bolts are often left up to the steel fabricator. With respect to joist and joist girders, the requirements for these components are set by the Wood Joist and Girder Institute. The most common joist in use is the K-series joist. Joist girders are joist that are designed to support joist just as girders support beams. When estimating joists and joist girders, the estimator needs to determine the number of joist and joist girders, their length, and their weights. The approximate weights for joist and joist girders are given in the Catalogue of Standard Specifications and Load Tables for Steel Joist and Joist Girders published by the Steel Joist Institute